A conventional signal transmission cable includes a plurality of parallelly arranged insulated conductors, and is used in various kinds of electrical appliances, electronic apparatus, computers, and communication apparatus to transmit signals.
In recent years, the soft circuit substrate technique has been widely employed in making signal transmission cables. Most currently available signal transmission cables employing the soft circuit substrate technique include a single-side, a double-side, a multisided, or a multilayer substrate according to the number of required transmission lines. That is, signal transmission cables using a double-side or a multilayer substrate may have increased number of transmission lines in the same one cable product. Moreover, the signal transmission cables employing the soft circuit substrate technique may have changeable pin arrangement through jumping connection.
The conventional signal transmission cables are only suitable for extending through a narrow flat space. However, pivoting mechanisms with round holes are often employed in many currently available electronic apparatus and communication apparatus. For example, the currently widely accepted mobile phones usually include a cover or a screen connected to a main unit of the mobile phone via a pivoting mechanism. At present, a miniaturized cable or a cluster of very fine conductors is used as a signal transmission cable to transmit electric signals from the main unit to the cover or the screen of the mobile phone.
When the signal transmission cable has a flat configuration, it can be easily extended through a narrow flat space without problems. However, it is also very important the cable can endure constant bending and/or can be bent frequently. The bending endurance is a common standard in determining the quality of a signal transmission cable. For a signal transmission cable having a single-side substrate, since all the conductors of the cable are arranged on only one surface of the soft circuit substrate, the cable generally presents relatively good bending endurance. However, for the signal transmission cable having a double-side, a multisided, or a multilayer substrate, conductors are differently arranged on two or more surfaces of the substrate and tend to be pulled and become useless after the cable has been bent many times. On the other hand, while the cable with a single-side substrate has better bending endurance, it includes fewer transmission lines and fails to meet actual need.